Hi ppl,

I'm looking for some advice after collecting my mazda 6 from my local garage a few weeks ago where it was in for a diagnostic check. This was following 2 warning lights appearing on my dashboard. After roughly an hour of driving the traction control and engine warning light would appear. The car drove no differently, pulled well through all the gears, idled fine, etc. Turning the car off then back on didn't clear it but they would go once the car had been stood overnight and would only re-appear once i'd driven it again for over an hour or so. The garage has pulled up these two error codes:
P1211 - Injector control pressure high/low
P2009 - Intake manifold air control actuator, bank 1 - circuit low
The garage can find no faults with these components and is at a bit of a loss to be honest so have cleared the faults and re-set the ECU. Since then i've run the car a few weeks now and the warning lights have returned. They seem to come and go now regardless of the journey time and the engine seems to be slightly down on power and is smoking quite a lot under load (black smoke) theres also a faint turbo whistle now but unsure if this was there before or if i'm being paranoid?
I'm going to book my car in with my garage again soon but it would be nice to have a clue where I can get my mechanic to start with his repair, so any thoughts would be gratefully received.

 

Too rich. I'd suggest replace the O2 sensor, but the P2009 air control actuator is probably not open enough. Cuircuit low could be a reference circuit signal, but in this case you need to locate it, probably clean or replace it. The O2 sensor and air filter air inlet has a flow sensor. Those two devices are used to calculate fuel schedule. I would think that would have thrown a code?
The reference signal could be from the return showing electrically the position it is in, and dosen't match the signal to it.

 

Thanks for the advice, I've forwarded your comments/recommendations on to my mechanic but he has come up with another possible cause which is the variable tumble control solenoid, any thoughts???